Loudspeakers are devices that transform an electrical signal into mechanical sound. FIG. 1 shows a cross-sectional view of the main components of loudspeaker 100. Rigid metal frame 101 attaches to magnet 102, which subjects air gap 108 between magnet 102 and frame 101 to a strong magnetic field. Lightweight diaphragm 103 attaches to frame 101 and to cylindrical shaped bobbin 107. Voice coil 104 is wound around bobbin 107, and it attaches through two voice coil wires 105 to two contacts 106. When an electrical current is run through voice coil 104, the magnetic field in air gap 108 interacts with the current in coil 104 to create a force that causes bobbin 107 to move up or down depending on the direction of that current. This physically moves the diaphragm (referred to as “loudspeaker excursion”), which in turn produces air pressure waves that result in audible sound.
Incidentally, loudspeakers are subject to failures resulting from mechanical stress, including voice coil wire breakage, damage of the diaphragm, diaphragm separating from the frame, etc. For instance, the voice coil moves with the diaphragm, but the wires of the voice coil attach to stationary contacts typically mounted on the loudspeaker frame. That is, these various wires move and change shape with every diaphragm movement, or with every sound made by the loudspeaker. And, if the loudspeaker excursion is too great, damage results.
Various technologies exist that reduce the chance of loudspeaker breakage. For example, wires may be given extra length for strain-relief; they may be pre-shaped to allow movement, etc. The loudspeaker may also be designed such that the wires move in free space, away from other surfaces that may cause friction damage.
Despite such technologies, however, loudspeaker components are still subject to mechanical deformation and stress. The inventors hereof have recognized that excessive loudspeaker excursion due to the application of a high power audio signal remains a problem.